Rapid Prototyping and Manufacturing (RP&M) is the name given to a field of technologies that can be used to form three-dimensional objects rapidly and automatically from three-dimensional computer data representing the objects. RP&M can be considered to include three classes of technologies: (1) Stereolithography, (2) Laminated Object Manufacturing, and (3) Selective Deposition Modeling.
The stereolithography class of technologies create three-dimensional objects based on the successive formation of layers of a fluid-like medium adjacent to previously formed layers of medium and the selective solidification of those layers according to cross-sectional data representing successive slices of the three-dimensional object in order to form and adhere laminae. One technology is known simply as stereolithography and uses a liquid medium which is selectively solidified by exposing it to prescribed stimulation. The liquid medium is typically a photopolymer and the prescribed stimulation is typically visible or ultraviolet electromagnetic radiation. Liquid-based stereolithography is disclosed in various patents, applications, and publications of which a number are briefly described in the Related Applications section hereinafter. Another stereolithography technology is known as Selective Laser Sintering (SLS). SLS is based on the selective solidification of layers of a powdered medium by exposing the layers to infrared electromagnetic radiation to sinter or fuse the particles. SLS is described in U.S. Pat. No. 4,863,538 issued Sep. 5, 1989 to Deckard. A third technology is known as Three-dimensional Printing (3DP). 3DP is based on the selective solidification of layers of a powdered medium which are solidified by the selective deposition of a binder thereon. 3DP is described in U.S. Pat. No. 5,204,055 issued Apr. 20, 1993 to Sachs.
Laminated Object Manufacturing, LOM, techniques involve the formation of three-dimensional objects by the stacking, adhering, and selective cutting of sheets of material, in a selected order, according to the cross-sectional data representing the three-dimensional object to be formed. LOM is described in U.S. Pat. No. 4,752,352 issued Jun. 21, 1988 to Feygin; and U.S Pat. No. 5,015,312 issued May 14, 1991 to Kinzie, and in PCT Publication No. WO 95-18009 issued Jul. 6, 1995 to Morita.
Selective Deposition Modeling, SDM, involves the build-up of three-dimensional objects by selectively depositing solidifiable material on a lamina-by-lamina basis according to cross-sectional data representing slices of the three-dimensional object. One such technique is called Fused Deposition Modeling, FDM, and involves the extrusion of streams of heated, flowable material which solidify as they are dispensed onto the previously formed laminae of the object. FDM is described in U.S. Pat. No. 5,121,329 issued Jun. 9, 1992 to Crump. Another technique is called Ballistic Particle Manufacturing, BPM, which uses a 5-axis, ink-jet dispenser to direct particles of a material onto previously solidified layers of the object. BPM is described in PCT publication numbers WO 96-12607 issued May 2, 1996 to Brown; WO 96-12608 issued May 2, 1996 to Brown; WO 96-12609 issued May 2, 1996 to Menhennett; and WO 96-12610 issued May 2, 1996 to Menhennett, all assigned to BPM Technology, Inc. A third technique is called Multijet Modeling, MJM, and involves the selective deposition of droplets of material from multiple ink jet orifices to speed the building process. MultiMate Modeling is described in PCT Publication Nos. WO 97-11835 issued Apr. 3, 1997 to Leyden et al. and WO 97-11837 issued Apr. 3, 1997 to Earl et al. (both assigned to 3D Systems, Inc. as is the instant application). A fourth example is Thermal Stereolithography (TSL) as described in U.S. Pat. No. 5,141,680 issued Aug. 25, 1992 to Almquist, et al.
When using SDM (as well as other RP&M building techniques), the appropriateness of various methods and apparatus for production of useful objects depends on a number of factors. As these factors cannot typically be optimized simultaneously, a selection of an appropriate building technique and associated method and apparatus involve trade-offs depending on specific needs and circumstances. Some factors to be considered may include 1) equipment cost, 2) operation cost, 3) production speed, 4) object accuracy, 5) object surface finish, 6) material properties of formed objects, 7) anticipated use of objects, 8) availability of secondary processes for obtaining different material properties, 9) ease of use and operator constraints, 10) required or desired operation environment, 11) safety, and 12) post processing time and effort.
In this regard there has been a long existing need to simultaneously optimize as many of these parameters as possible to more effectively build three-dimensional objects. As a first example, there has been a need to enhance object production speed and lower set up time and file preparation time when building objects using a Selective Deposition Modeling technique (SDM) while simultaneously maintaining or reducing the equipment cost. A critical problem in this regard has been the need for an efficient technique for printing raster lines for three-dimensional objects using different numbers of jets.
Accordingly, there is a long-felt but unmet need for methods and apparatus to print raster lines in a Selective Deposition Modeling system to overcome the disadvantages of the prior art.
Though, as noted above, the techniques of the instant invention are directed primarily to selective deposition modeling object formation, it is believed that the techniques may have application in other RP&M technologies.
All patents referred to in this section of the specification are hereby incorporated by reference as if set forth in full.